1. The Field of the Invention
The present disclosure relates generally to trailer hitch systems and accessories, and more particularly, but not necessarily entirely, to trailer hitch accessories for reducing sway of trailers.
2. Description of Related Art
Various different types of trailer hitches are known in the art for attaching trailers to towing vehicles. One of the most common types of towing systems utilizes a ball hitch. Typical ball hitches have a generally spherical shaped ball with a stem or threaded rod extending from a base of the ball. The threaded rod may be configured to engage a hitch head mounted on the towing vehicle using a threaded receiver or ball hitch fitting. A trailer coupling member, positioned on a front of the trailer tongue, may engage the ball hitch in a loose friction fit, and may be secured to the ball in preparation for towing.
One of the biggest safety concerns with towing trailers is that the trailers may sway, leading to loss of control of the towing vehicle. A number of factors may contribute to sway, including: side winds, passing vehicles, quick lane changes, uneven roads and sudden stops. Some trailer hitches may not handle these situations well and may often enhance the sway problem making driving even more stressful and difficult.
Another common problem encountered when towing a trailer is “highway hop,” or the bouncing that often happens to trailers on uneven roadways. This problem may be caused by uneven weight distribution. With ordinary ball-type hitches, most of the trailer tongue weight may be carried on the back axle of the tow vehicle. This may raise the front end of the tow vehicle. The uneven distribution of weight may make steering control more difficult, especially during emergency situations. Weight distribution allows a trailer and tow vehicle to be level. Risks associated with driving a trailer without a weight distribution hitch may include loss of steering control, braking difficulties, and hitch dragging.
Some hitches include load equalizing systems utilizing spring arms or bars to distribute loads and allow the towing vehicle and trailer to remain level. One end of the spring arms may be attached under the ball hitch and hitch head. The spring arms may extend from the hitch head towards the trailer, and may be joined to the trailer tongue using chains and/or brackets. The end of the spring arms opposite the hitch head may be lifted or loaded to place an upward force on the hitch head to thereby equalize the load exerted on the trailer hitch. Various mechanisms are known for use in association with a trailer hitch to reduce side sway of the trailer as well as to equalize loads.
Some prior art embodiments of the brackets for joining the spring bars to the trailer tongue have been formed as rigid members, whereas other embodiments of the brackets have been formed as flexible members, such as chains. A drawback of the prior art brackets formed as flexible members is that the flexible members or chains may not provide stabilizing support to the spring bars and may allow the spring bars to swing back and forth in the manner of a pendulum.
Contact between the rigid brackets and the spring bars may help to reduce sway of the trailer. However, sometimes the contact between the spring bar and the brackets may cause noise. If the noise is excessive, or if increased maneuverability of the trailer is desired, it may be beneficial to reduce the friction between the spring bars and the rigid brackets. In other circumstances, it may be desirable to increase the friction between the spring bars and the rigid brackets to increase sway control.
Other trailer hitch systems are known to place a cam surface on the rigid brackets to modify movement of the spring bar with respect to the rigid bracket. For example, a convex cam surface may be formed on the bracket that interacts with a corresponding concave shape, or cam follower, on the spring bars. The shape of the cam surface on the bracket with respect to the cam follower on the spring bar may be configured to bias the spring bar in a neutral position with respect to the bracket, in which the cam follower mates with the cam. As the spring bar moves away from the neutral position in which the cam and cam follower are mated, the biasing force caused by the shapes of the cam and the cam follower tend to move spring bar back to the mated position on the bracket to thereby add stability to the trailer hitch system. Brackets having convex cam surfaces are disclosed in U.S. Pat. Nos. 3,194,584, 3,730,554 and 6,419,257, for example.
Despite the advantages of the known trailer hitches, improvements are still being sought. The prior art is characterized by several disadvantages that may be addressed by the present disclosure. The present disclosure minimizes, and in some aspects eliminates, the failures of the prior art, by utilizing the methods and structural features described herein.
The features and advantages of the disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the disclosure without undue experimentation. The features and advantages of the disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.